Knees Hurt? Blame Your Feet

Flat feet may cause knee osteoarthritis, according to study

(RxWiki News) "Flat-footed" older adults may be more likely to experience chronic knee pain than their peers who have higher arches, according to a new study from Boston University School of Medicine.

Flat feet (low arches) can contribute to osteoarthritis in the knee, which results from years of "wear 'n' tear" in which cartilage cushioning in the joint breaks down.

The study followed 1,900 adults aged 50 or older and found those with the flattest feet were 31 percent more likely to experience knee pain most days and 43 percent more likely to show damage to the cartilage inside the knee joint.

Lead author K. Douglas Gross, a clinical research associate at Boston University School of Medicine, said that although the study doesn't prove the flat feet-arthritis link, there is reason to believe flat feet act as the culprit.

Gross said that when feet flatten, it changes posture and the way people move. A possible consequence of this shift may be that, when a person puts weight on a flat foot, their lower legs rotates inward, which can cause damage to the cartilage.

The findings present a chicken-or-egg scenario to researchers, however.

"We don't know which came first," Gross said, meaning the flat feet or the osteoarthritis.

Arch supports generally provide relief to flat-footed patients, but Gross said the study was too preliminary to recommend flat-footed older adults rush out and buy them.

Osteoarthritis is a common condition in older adults. Knee osteoarthritis affects about 9 million Americans, more than half of whom are over 65. A government study in 2008 projected that as many as 46 percent of Americans will develop arthritis in at least one knee by age 85.

Review Date: 
January 26, 2011